EP0380192A1 - Process and apparatus for indirectly heating a process gas stream in a reaction space for an endothermal reaction - Google Patents

Process and apparatus for indirectly heating a process gas stream in a reaction space for an endothermal reaction Download PDF

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Publication number
EP0380192A1
EP0380192A1 EP90250017A EP90250017A EP0380192A1 EP 0380192 A1 EP0380192 A1 EP 0380192A1 EP 90250017 A EP90250017 A EP 90250017A EP 90250017 A EP90250017 A EP 90250017A EP 0380192 A1 EP0380192 A1 EP 0380192A1
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EP
European Patent Office
Prior art keywords
flue gas
reaction space
heat
reactor
walls
Prior art date
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Granted
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EP90250017A
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German (de)
French (fr)
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EP0380192B1 (en
Inventor
Maurizio Dr. Bezzeccheri
Lorena Mosca
Francesco Giacobbe
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Vodafone GmbH
Technip Holding Benelux BV
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Mannesmann AG
KTI Group BV
Kinetics Technology International Group BV
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J8/00Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
    • B01J8/02Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds
    • B01J8/06Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds in tube reactors; the solid particles being arranged in tubes
    • B01J8/062Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds in tube reactors; the solid particles being arranged in tubes being installed in a furnace
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J19/00Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J19/24Stationary reactors without moving elements inside
    • B01J19/2415Tubular reactors
    • B01J19/2425Tubular reactors in parallel
    • CCHEMISTRY; METALLURGY
    • C01INORGANIC CHEMISTRY
    • C01BNON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B3/00Hydrogen; Gaseous mixtures containing hydrogen; Separation of hydrogen from mixtures containing it; Purification of hydrogen
    • C01B3/02Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen
    • C01B3/32Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of gaseous or liquid organic compounds with gasifying agents, e.g. water, carbon dioxide, air
    • C01B3/34Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of gaseous or liquid organic compounds with gasifying agents, e.g. water, carbon dioxide, air by reaction of hydrocarbons with gasifying agents
    • C01B3/38Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of gaseous or liquid organic compounds with gasifying agents, e.g. water, carbon dioxide, air by reaction of hydrocarbons with gasifying agents using catalysts
    • C01B3/384Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of gaseous or liquid organic compounds with gasifying agents, e.g. water, carbon dioxide, air by reaction of hydrocarbons with gasifying agents using catalysts the catalyst being continuously externally heated
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2208/00Processes carried out in the presence of solid particles; Reactors therefor
    • B01J2208/00008Controlling the process
    • B01J2208/00017Controlling the temperature
    • B01J2208/00477Controlling the temperature by thermal insulation means
    • B01J2208/00495Controlling the temperature by thermal insulation means using insulating materials or refractories
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2208/00Processes carried out in the presence of solid particles; Reactors therefor
    • B01J2208/00008Controlling the process
    • B01J2208/00017Controlling the temperature
    • B01J2208/00504Controlling the temperature by means of a burner
    • CCHEMISTRY; METALLURGY
    • C01INORGANIC CHEMISTRY
    • C01BNON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B2203/00Integrated processes for the production of hydrogen or synthesis gas
    • C01B2203/08Methods of heating or cooling
    • C01B2203/0805Methods of heating the process for making hydrogen or synthesis gas
    • C01B2203/0811Methods of heating the process for making hydrogen or synthesis gas by combustion of fuel
    • CCHEMISTRY; METALLURGY
    • C01INORGANIC CHEMISTRY
    • C01BNON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B2203/00Integrated processes for the production of hydrogen or synthesis gas
    • C01B2203/08Methods of heating or cooling
    • C01B2203/0805Methods of heating the process for making hydrogen or synthesis gas
    • C01B2203/0811Methods of heating the process for making hydrogen or synthesis gas by combustion of fuel
    • C01B2203/0816Heating by flames
    • CCHEMISTRY; METALLURGY
    • C01INORGANIC CHEMISTRY
    • C01BNON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B2203/00Integrated processes for the production of hydrogen or synthesis gas
    • C01B2203/08Methods of heating or cooling
    • C01B2203/0805Methods of heating the process for making hydrogen or synthesis gas
    • C01B2203/0866Methods of heating the process for making hydrogen or synthesis gas by combination of different heating methods

Definitions

  • the invention relates to a method for indirect heating of a process gas stream in a reaction chamber for an endothermic, in particular catalytic reaction according to the preamble of claim 1 and a device for performing this method.
  • a possible field of application of the invention is the catalytic steam reforming of hydrocarbons to produce a hydrogen-rich gas.
  • a mixture of water vapor, hydrocarbon and / or carbon dioxide is used as the process gas.
  • This gas mixture is fed at temperatures of approximately 400 to 600 degrees C at pressures of up to 4 MPa to a reaction chamber, which can consist of several catalyst-filled tubes, and heated there to approximately 750 to 900 degrees C.
  • This gas mixture then reacts endothermically over the catalyst to a hydrogen-rich gas with proportions of carbon monoxide, carbon dioxide and excess water vapor and hydrocarbon.
  • the hydrogen content of the product gas generated depends, among other things. from the excess of the water vapor used and from the temperature and pressure in the catalyst-filled tube. An increase in the excess of steam and the temperature in the catalyst-filled tube cause an increase in the hydrogen production, while an increase in pressure results in a decrease in the same.
  • a device for carrying out an endothermic catalytic reaction of a process gas stream is known from EP 0 194 067 B1.
  • This has a housing with one or more catalyst-filled tubes arranged therein parallel to one another, each with a blind end. Means are provided in the housing for the supply and discharge of a flue gas for heating the outer surface of the catalyst-filled tubes, through the interior of which the process gas stream is passed under heat absorption.
  • the catalyst-filled tubes are each surrounded by a tubular jacket which forms an annular gap with the tube. The jacket extends over the greater part of the length of the catalyst-filled tube.
  • the feed line for the flue gas is aimed directly at the blind end of the catalyst-filled pipe.
  • the direct inflow of the catalyst-filled tube through the hot flue gas proves to be disadvantageous, since the thermal load on the blind end of the catalyst-filled tube is thereby very high.
  • the temperature in the jacket of the catalyst-filled tube is so high that it is damaged after a relatively short time and must be replaced if the flue gas is not cooled accordingly beforehand. This could be done, for example, by an upstream heat exchanger or by mixing it with already cooled flue gas. Both measures require corresponding additional structural effort.
  • the flue gas simultaneously absorbs heat from the heated barrier, its temperature is kept almost constant despite the heat being given off to the reaction space in the area of the barrier, which extends only over part of the length of the reaction space. Outside the area of the barrier, the flue gas cools relatively quickly on its way along the reaction space, so that the temperature in the reaction space has a corresponding gradient.
  • the object of the present invention is to optimize the thermal conditions for an endothermic reaction, in particular a catalytic reaction, in such a way that largely isothermal conditions in the entire reaction space are available.
  • reaction chamber should no longer have a strong temperature gradient, as usual, at which the desired endothermic reaction takes place in the different areas with correspondingly different intensities, but that better use of the reaction chamber should be achieved by the fact that almost everywhere equally good reaction conditions are created in thermal terms.
  • the invention takes advantage of the knowledge gained from EP 89 250 073.7 and expands its field of application considerably by providing that the indirect heat exchange between the flow sections of one and the same flue gas flow along the opposite side of a heat-conducting barrier runs over the entire axial length of the Reaction space is maintained. It is thereby achieved that the heat dissipation in the flow section of the flue gas, which faces the walls of the reaction space, can be partially compensated for by the heat absorption, which can take place from the opposite flow section of the flue gas through the heat-conducting barrier.
  • the temperature of the flue gas conducted past the walls of the reaction chamber in direct contact therefore decreases comparatively slowly, despite the constant heat transfer to the reaction chamber which takes place by convection.
  • the process gas can be preheated using the heat still contained in the derived cooled flue gas.
  • the invention makes it possible to optimally use a reaction space of a given size by keeping the temperature at a constant maximum value almost everywhere. This maximum value is chosen so that the permissible thermal stresses of the materials used for the reactor are not exceeded and, at the same time, the most favorable thermal conditions are available for the respective chemical reaction.
  • the reactor 5 shown in FIG. 1 has a reaction chamber 1 with an outer cylindrical jacket 2.
  • the reaction chamber 1 is essentially ring-shaped because it has a cylindrical recess 3 on the inside, which is delimited by an inner wall 4 made of a material that is a good conductor of heat.
  • a preheated process gas for example ethylbenzene vapors
  • This process gas first flows into an annular distribution space 22 and from there up into the actual reaction space 1, which is filled, for example, with a catalyst. After flowing through the catalyst mass, the process gas is converted into a product gas (eg styrene) and exits from the reaction chamber 1 at the upper end 12 of the reactor 5 through the product gas discharge line 7. In order to keep the endothermic reaction in reaction space 1 going, it must be heated by means of a hot flue gas.
  • a product gas eg styrene
  • a flue gas feed line 10 is provided at the lower end 13 of the reactor 5, through which hot flue gases are fed directly into the cylindrical recess 3.
  • the flue gas feed line 10 is advantageously designed as a combustion chamber 16 with refractory walls 15, so that the flue gas can be generated directly in the reactor 5.
  • the combustion chamber 16 has a burner 19 at the lower end, to which fuel and an oxygen-containing gas can be supplied via the lines 20 and 21.
  • a flue gas supply line 10 is directly connected to a barrier designed as a tubular body 8 made of a material which is a good heat conductor.
  • This gas-tight tubular body 8 which extends close to the upper end of the cylindrical recess 3, initially shields the inner wall 4 of the reaction chamber 1 from direct contact with the hot flue gas and forms an annular gap 9 with the wall 4.
  • This annular gap 9 is open at the top to the interior of the cylindrical recess 3.
  • the hot flue gas generated by the burner 19 therefore initially flows upwards along the tubular body 8, is deflected outwards at the upper end of the tubular body 8 and finally flows downwards in the opposite direction on the outside of the tubular body 8 through the annular gap 9 where it can be discharged through the flue gas discharge line 11 located at the lower end 13.
  • the flue gas flowing downward through the annular gap 9 continuously gives off heat via the wall 4 to the process gas flowing in countercurrent through the reaction space 1 and enables the endothermic reaction there. Since at the same time hot flue gas flows along the inside of the tubular body 8 and emits heat to the tubular body 8, part of this heat is transferred to the downward flowing section of the flue gas stream, so that its temperature decreases comparatively slowly despite the continuous heat emission to the process gas.
  • the extent of the heat exchange between the two flow sections of the flue gas flow and between the downward flowing flue gas flow and the process gas flow can be influenced by the choice of the diameter of the tubular body, since a larger diameter, with otherwise the same conditions, reduces the annular gap 9 and thus increases the flow velocity in the causes downward flow section of the flue gas, so that the flue gas due to the intensified heat exchange (convection) with the inner wall 4 of the reaction chamber 1 enters the flue gas discharge line 11 at a lower temperature.
  • the heat exchange between the two oppositely directed flow sections of the flue gas can be influenced particularly effectively by arranging a flow displacement body 14 in the interior of the cylindrical recess 3 in the region of its longitudinal axis, which body extends approximately over the length of the tubular body 8 and the upward-facing one Flow section of the flue gas stream in the vicinity of the inner surface of the tubular body 8 holds.
  • the flow rate of the upward flue gas stream increases in accordance with the reduction in cross section, so that an improved heat exchange by convection takes place.
  • the flue gas flowing upward from the combustion chamber 16 along the tubular body 8 leads to a strong heating of the wall of the tubular body 8, the temperature of which decreases with increasing height. Therefore, the heat radiation from the wall of the tubular body 8 to the wall 4 of the reaction chamber 1 is significantly stronger in the lower part than in the upper part. This leads to an extensive compensation of the temperature in the wall 4 over the length of the reaction space 1, so that largely isothermal conditions also occur in the interior of the reaction space 1.
  • the reaction chamber 1 is designed with an approximately dome-shaped bottom 18 on the inside. Because of the constant heat emission in the area of the upward flue gas stream, its temperature can be reduced at least to such an extent that the direct contact of the flue gas with the mechanically stressed inner wall until the upper end of the tubular body 8 and thus until the dome-shaped bottom 18 is reached 4 of the reaction chamber 1 no longer leads to thermal damage.
  • the outside of the reactor 5 can be provided with thermal insulation 17, which reduces the radiation losses.
  • the burner generates a flue gas with a very high temperature
  • return part of the cooled flue gas which is discharged through the flue gas discharge line 11, to the burner 19 or the combustion chamber 16 in order to return the flue gas temperature there to diminish.
  • the heat exchange between the flue gas and the process gas is expediently carried out in a countercurrent process, in particular if the preheating of the process gas does not take place to the reaction temperature, it is nevertheless not impossible to carry out the invention according to the direct current principle.
  • the housing in the lower part 13 of the reactor 5 is made of refractory material, as is the flow displacement body 14, which can be designed as a solid rod or as a tube with at least one closed end.
  • Metallic materials are recommended for the casing 2, the walls 4 and the tubular body 8.
  • FIG. 2 shows a modified embodiment of the invention, functionally identical parts being provided with the same reference numerals as in FIG. 1.
  • the reactor 5 shown there has a plurality of cylindrical recesses 3, which are arranged parallel to one another and whose cylindrical walls 8 are each gas-tightly connected to the holes in a perforated base 24.
  • the tubular bodies 8 coaxially inserted into the recesses 3 from below are each gas-tightly connected to the holes of a second perforated base 23, which closes off the combustion chamber 16 at the top, so that the hot flue gases inevitably rise upwards through the tubular bodies 8, on the latter upper ends in the region of the dome-shaped bottoms 18 are each deflected and guided downward through the annular gaps 9.
  • the heat exchange between the flue gas flow sections and the process gas takes place in the same way as in Figure 1. After flowing through the annular gaps 9, the cooled flue gas collects in the space between the two perforated plates 23 and 24 and then exits through the flue gas discharge line 11 from the bottom of the housing of the reactor 5 out.
  • the reactor is extremely simple in construction and therefore causes comparatively low production costs.
  • the heat flow through the wall of the reaction chamber is uniform and can be approximated to an optimal maximum value that takes full account of the thermal load-bearing capacity of the materials used. Problems due to direct exposure to mechanically stressed parts from an open flame or too hot flue gases are avoided. Since the endothermic reaction can practically take place under isothermal conditions, a high efficiency of the reaction space volume is ensured. Thanks to the comparatively small design that is possible with a given output, the radiation losses can be minimized. No fireproof materials are required for external heat insulation; these are only recommended in the area of flue gas supply and discharge.

Abstract

Heat from hot flue gas absorbed by walls is released to the process gas, the flue gas being directed by baffles. To create largely isothermal conditions in the reaction space, the hot flue gas is passed along the baffle over the entire axial length of the reaction space, and the flow velocity of the flue gas stream is influenced in such a way that the heat-absorbing walls of the reaction space are largely at the same temperatures over the axial length. <IMAGE>

Description

Die Erfindung betrifft ein Verfahren zur indirekten Beheizung eines Prozeßgasstroms in einem Reaktionsraum für eine endotherme, insbesondere katalytische Reaktion gemäß dem Oberbegriff des Patentanspruchs 1 und eine Vorrichtung zur Durchführung dieses Verfahrens.The invention relates to a method for indirect heating of a process gas stream in a reaction chamber for an endothermic, in particular catalytic reaction according to the preamble of claim 1 and a device for performing this method.

Ein mögliches Einsatzgebiet der Erfindung stellt die katalytische Dampfreformierung von Kohlenwasserstoffen zur Herstellung eines wasserstoffreichen Gases dar. Als Prozeßgas dient ein Gemisch aus Wasserdampf, Kohlenwasserstoff und/oder Kohlendioxyd. Dieses Gasgemisch wird mit Temperaturen von etwa 400 bis 600 Grad C bei Drücken von bis zu 4 MPa einem Reaktionsraum, der aus mehreren katalysatorgefüllten Rohren bestehen kann, zugeführt und dort auf ca. 750 bis 900 Grad C aufgeheizt. Über dem Katalysator reagiert dieses Gasgemisch dann endotherm zu einem wasserstoffreichen Gas mit Anteilen von Kohlenmonoxyd, Kohlendioxyd und Überschüssen an Wasserdampf und Kohlenwasserstoff.A possible field of application of the invention is the catalytic steam reforming of hydrocarbons to produce a hydrogen-rich gas. A mixture of water vapor, hydrocarbon and / or carbon dioxide is used as the process gas. This gas mixture is fed at temperatures of approximately 400 to 600 degrees C at pressures of up to 4 MPa to a reaction chamber, which can consist of several catalyst-filled tubes, and heated there to approximately 750 to 900 degrees C. This gas mixture then reacts endothermically over the catalyst to a hydrogen-rich gas with proportions of carbon monoxide, carbon dioxide and excess water vapor and hydrocarbon.

Der Wasserstoffgehalt des erzeugten Produktgases hängt u.a. vom Überschuß des verwendeten Wasserdampfes sowie von der Temperatur und dem Druck im katalysatorgefüllten Rohr ab. Ein Ansteigen des Wasserdampfüberschusses und der Temperatur im katalysatorgefüllten Rohr bewirken eine Zunahme der Wasserstoffgewinnung, während eine Druckerhöhung eine Abnahme derselben zur Folge hat.The hydrogen content of the product gas generated depends, among other things. from the excess of the water vapor used and from the temperature and pressure in the catalyst-filled tube. An increase in the excess of steam and the temperature in the catalyst-filled tube cause an increase in the hydrogen production, while an increase in pressure results in a decrease in the same.

Aus der EP 0 194 067 B1 ist eine Vorrichtung zur Durchführung einer endothermen katalytischen Reaktion eines Prozeßgasstroms bekannt. Diese weist ein Gehäuse mit einem oder mehreren darin parallel zueinander angeordneten katalysatorgefüllten Rohren mit je einem blinden Ende auf. Im Gehäuse sind Mittel für die Zuführung und Abführung eines Rauchgases zur Beheizung der äußeren Oberfläche der katalysatorgefüllten Rohre, durch deren Inneres der Prozeßgasstrom unter Wärmeaufnahme hindurchgeführt wird, vorgesehen. Die katalysatorgefüllten Rohre sind jeweils von einem rohrförmigen Mantel, der mit dem Rohr einen Ringspalt bildet, umgeben. Der Mantel erstreckt sich über den größeren Teil der Länge des katalysatorgefüllten Rohres. Die Zuleitung für das Rauchgas ist unmittelbar auf das blinde Ende des katalysatorgefüllten Rohres gerichtet. Die dadurch bewirkte direkte Anströmung des katalysatorgefüllten Rohres durch das heiße Rauchgas erweist sich als nachteilig, da hierdurch die thermische Belastung des blinden Endes des katalysatorgefüllten Rohres sehr hoch ist. An kritischen Stellen entstehen im Mantel des katalysatorgefüllten Rohres so hohe Temperaturen, daß es nach relativ kurzer Zeit beschädigt ist und ausgewechselt werden muß, wenn man nicht vorher für eine entsprechende Abkühlung des Rauchgases sorgt. Dies könnte beispielsweise durch einen vorgeschalteten Wärmetauscher oder durch Vermischung mit bereits abgekühltem Rauchgas geschehen. Beide Maßnahmen erfordern entsprechenden zusätzlichen baulichen Aufwand.A device for carrying out an endothermic catalytic reaction of a process gas stream is known from EP 0 194 067 B1. This has a housing with one or more catalyst-filled tubes arranged therein parallel to one another, each with a blind end. Means are provided in the housing for the supply and discharge of a flue gas for heating the outer surface of the catalyst-filled tubes, through the interior of which the process gas stream is passed under heat absorption. The catalyst-filled tubes are each surrounded by a tubular jacket which forms an annular gap with the tube. The jacket extends over the greater part of the length of the catalyst-filled tube. The feed line for the flue gas is aimed directly at the blind end of the catalyst-filled pipe. The direct inflow of the catalyst-filled tube through the hot flue gas proves to be disadvantageous, since the thermal load on the blind end of the catalyst-filled tube is thereby very high. At critical points, the temperature in the jacket of the catalyst-filled tube is so high that it is damaged after a relatively short time and must be replaced if the flue gas is not cooled accordingly beforehand. This could be done, for example, by an upstream heat exchanger or by mixing it with already cooled flue gas. Both measures require corresponding additional structural effort.

Zur Abmilderung der thermischen Belastung der katalysatorgefüllten Rohre ist es bekannt, diese auf ihrer Außenseite mit einer keramischen Schutzummantelung im Bereich der direkten Beaufschlagung mit dem heißen Rauchgas zu versehen. Ein Nachteil derartiger Schutzummantelungen liegt in der Anfälligkeit gegenüber Wärmedehnungsspannungen, die zu Beschädigungen der Keramik und dann lediglich mit zeitlicher Verzögerung auch zu Beschädigungen der katalysatorgefüllten Rohre selbst führen.To alleviate the thermal load on the catalyst-filled pipes, it is known to provide them on the outside with a ceramic protective coating in the area of direct exposure to the hot flue gas. A disadvantage of such protective sheathing lies in the susceptibility to thermal expansion stresses, which lead to damage to the ceramic and then only with a time delay to damage to the catalyst-filled tubes themselves.

In der auf die Anmelder zurückgehenden, nicht vorveröffentlichten Patentanmeldung EP 89 250 073.7 wird zur Lösung der Überhitzungsproblematik der Wände eines Reaktionsraums vorgeschlagen, das zur Beheizung der Reaktionsraumwände verwendete heiße Rauchgas zunächst an einer Barriere aus einem temperaturbeständigen und gut wärmeleitenden Material entlangzuführen und dabei Wärme an diese Barriere abgeben zu lassen, bis es eine für die Reaktionsraumwände unschädliche Temperatur erreicht hat. Erst dann wird der Strom des Rauchgases umgelenkt und in entgegengesetzter Richtung auf der anderen Seite der Barriere weitergeführt, wobei das bereits etwas abgekühlte Rauchgas mit den Wänden des Reaktionsraums in direkten Kontakt tritt und Wärme an diese Wände abgibt. Da das Rauchgas jedoch gleichzeitig von der aufgeheizten Barriere Wärme aufnimmt, wird seine Temperatur trotz der Wärmeabgabe an den Reaktionsraum im Bereich der Barriere, die sich nur über einen Teil der Länge des Reaktionsraums erstreckt, nahezu konstant gehalten. Außerhalb des Bereichs der Barriere kühlt das Rauchgas auf seinem Weg entlang des Reaktionsraums relativ rasch ab, so daß die Temperatur im Reaktionsraum ein entsprechendes Gefälle aufweist.In the non-prepublished patent application EP 89 250 073.7, which goes back to the applicants, it is proposed to solve the overheating problem of the walls of a reaction space that the hot flue gas used for heating the reaction space walls is first passed along a barrier made of a temperature-resistant and good heat-conducting material and thereby heat to it Have the barrier released until it has reached a temperature that is harmless to the reaction chamber walls. Only then is the flow of the flue gas redirected and continued in the opposite direction on the other side of the barrier, the flue gas, which has already cooled somewhat, coming into direct contact with the walls of the reaction space and giving off heat to these walls. However, since the flue gas simultaneously absorbs heat from the heated barrier, its temperature is kept almost constant despite the heat being given off to the reaction space in the area of the barrier, which extends only over part of the length of the reaction space. Outside the area of the barrier, the flue gas cools relatively quickly on its way along the reaction space, so that the temperature in the reaction space has a corresponding gradient.

Während in der EP 89 250 073.7 lediglich die thermische Schädigung der Wände des Reaktionsraums vermieden werden sollte, liegt der vorliegenden Erfindung die Aufgabe zugrunde, die thermischen Bedingungen für eine endotherme Reaktion, insbesondere eine katalytische Reaktion dahingehend zu optimieren, daß im gesamten Reaktionsraum weitgehend isotherme Verhältnisse vorliegen.While in EP 89 250 073.7 only the thermal damage to the walls of the reaction space should be avoided, the object of the present invention is to optimize the thermal conditions for an endothermic reaction, in particular a catalytic reaction, in such a way that largely isothermal conditions in the entire reaction space are available.

Das bedeutet, daß der Reaktionsraum nicht mehr wie bisher üblich ein starkes Temperaturgefälle aufweisen soll, bei dem die gewünschte endotherme Reaktion in den verschiedenen Bereichen mit entsprechend stark unterschiedlicher Intensität abläuft, sondern daß eine bessere Nutzung des Reaktionsraums dadurch erreicht werden soll, daß nahezu überall etwa gleichgute Reaktionsbedingungen in thermischer Hinsicht geschaffen werden.This means that the reaction chamber should no longer have a strong temperature gradient, as usual, at which the desired endothermic reaction takes place in the different areas with correspondingly different intensities, but that better use of the reaction chamber should be achieved by the fact that almost everywhere equally good reaction conditions are created in thermal terms.

Gelöst wird diese Aufgabe durch ein Verfahren, das die Merkmale des Patentanspruchs 1 aufweist und durch die kennzeichnenden Merkmale des Patentanspruchs 2 in vorteilhafter Weise weitergebildet wird. Eine Vorrichtung zur Durchführung dieses Verfahrens ist im Patentanspruch 3 angegeben. Die kennzeichnenden Merkmale der Unteransprüche 4 bis 11 stellen vorteilhafte Ausgestaltungen der erfindungsgemäßen Vorrichtung dar.This object is achieved by a method which has the features of patent claim 1 and is advantageously further developed by the characterizing features of patent claim 2. A device for performing this method is specified in claim 3. The characteristic features of subclaims 4 to 11 represent advantageous embodiments of the device according to the invention.

Die Erfindung macht sich die Erkenntnisse aus der EP 89 250 073.7 zunutze und erweitert deren Anwendungsbereich beträchtlich, indem sie vorsieht, daß der indirekte Wärmeaustausch zwischen den in entgegengesetzter Richtung auf gegenüberliegenden Seiten einer wärmeleitenden Barriere entlanggeführten Strömungsabschnitten ein und desselben Rauchgasstromes über die gesamte axiale Länge des Reaktionsraumes hinweg aufrechterhalten wird. Dadurch wird erreicht, daß die Wärmeabgabe in dem Strömungsabschnitt des Rauchgases, der den Wänden des Reaktionsraums zugekehrt ist, zu einem Teil ausgeglichen werden kann durch die Wärmeaufnahme, die von dem entgegengerichteten Strömungsabschnitt des Rauchgases aus durch die wärmeleitende Barriere hindurch erfolgen kann. Die Temperatur des an den Wänden des Reaktionsraums in direktem Kontakt vorbeigeführten Rauchgases vermindert sich daher trotz der durch Konvektion erfolgenden ständigen Wärmeabgabe an den Reaktionsraum vergleichsweise langsam.The invention takes advantage of the knowledge gained from EP 89 250 073.7 and expands its field of application considerably by providing that the indirect heat exchange between the flow sections of one and the same flue gas flow along the opposite side of a heat-conducting barrier runs over the entire axial length of the Reaction space is maintained. It is thereby achieved that the heat dissipation in the flow section of the flue gas, which faces the walls of the reaction space, can be partially compensated for by the heat absorption, which can take place from the opposite flow section of the flue gas through the heat-conducting barrier. The temperature of the flue gas conducted past the walls of the reaction chamber in direct contact therefore decreases comparatively slowly, despite the constant heat transfer to the reaction chamber which takes place by convection.

Andererseits findet ein Wärmetausch zwischen der Barriere und den Wänden des Reaktionsraums infolge Wärmestrahlung statt. Über die axiale Länge des Reaktionsraums verhält sich die Intensität dieser Wärmestrahlung tendenziell umgekehrt wie die Rauchgastemperatur in dem den Reaktionsraumwänden zugekehrten Strömungsabschnitt. Dies hat zur Folge, daß die Wände des Reaktionsraumes, durch die hindurch der Wärmetausch erfolgt, sich nahezu auf die gleiche Temperatur erwärmen und sich auch im Reaktionsraum trotz der stattfindenden endothermen Reaktionsvorgänge überall eine etwa gleichhohe Temperatur ausbildet, wobei diese auf eine optimale Höhe (in Abhängigkeit von der Art der Reaktion) eingestellt werden kann.On the other hand, there is a heat exchange between the barrier and the walls of the reaction space due to heat radiation. Over the axial length of the reaction space, the intensity of this heat radiation tends to be inversely like the flue gas temperature in the flow section facing the reaction space walls. The result of this is that the walls of the reaction space through which the heat exchange takes place heat up to almost the same temperature and, despite the endothermic reaction processes taking place, an approximately equally high temperature is formed everywhere in the reaction space, this being at an optimal height (in Depending on the type of reaction) can be set.

Voraussetzung hierfür ist allerdings, daß der in den Reaktionsraum eingeführte Prozeßgasstrom bereits etwa auf Reaktionstemperatur vorgewärmt wurde. Anderenfalls entsteht selbstverständlich eine Zone geringerer Temperatur im Reaktionsraum, innerhalb der sich die Aufheizung auf Reaktionstemperatur vollzieht. Die Vorwärmung des Prozeßgases kann unter Ausnutzung der in dem abgeleiteten abgekühlten Rauchgas noch enthaltenen Wärme vorgenommen werden.The prerequisite for this, however, is that the process gas stream introduced into the reaction space has already been preheated to about the reaction temperature. Otherwise, of course, a zone of lower temperature is created in the reaction space, within which the heating to reaction temperature takes place. The process gas can be preheated using the heat still contained in the derived cooled flue gas.

Die Erfindung ermöglicht es, einen Reaktionsraum gegebener Größe optimal zu nutzen, indem die Temperatur nahezu überall auf einem konstanten Maximalwert gehalten wird. Dieser Maximalwert wird so gewählt, daß die zulässigen thermischen Beanspruchungen der für den Reaktor verwendeten Werkstoffe nicht überschritten werden und gleichzeitig für die jeweilige chemische Reaktion möglichst günstige thermische Bedingungen vorliegen.The invention makes it possible to optimally use a reaction space of a given size by keeping the temperature at a constant maximum value almost everywhere. This maximum value is chosen so that the permissible thermal stresses of the materials used for the reactor are not exceeded and, at the same time, the most favorable thermal conditions are available for the respective chemical reaction.

Im folgenden wird die Erfindung anhand der in den Figuren 1 und 2 dargestellten Ausführungsbeispiele näher beschrieben. Es zeigen:

  • Figur 1 einen erfindungsgemäßen Reaktor mit einer zylindrischen Aussparung im Reaktionsraum,
  • Figur 2 einen erfindungsgemäßen Reaktor mit mehreren zylindrischen Aussparungen im Reaktionsraum.
The invention is described in more detail below with reference to the exemplary embodiments illustrated in FIGS. 1 and 2. Show it:
  • FIG. 1 shows a reactor according to the invention with a cylindrical recess in the reaction space,
  • Figure 2 shows a reactor according to the invention with several cylindrical recesses in the reaction chamber.

Der in Figur 1 dargestellte Reaktor 5 hat einen Reaktionsraum 1 mit einem äußeren zylinderförmigen Mantel 2. Der Reaktionsraum 1 ist im wesentlichen ringförmig ausgebildet, da er innen eine zylinderförmige Aussparung 3 aufweist, die von einer inneren Wand 4 aus einem gut wärmeleitenden Material begrenzt ist.The reactor 5 shown in FIG. 1 has a reaction chamber 1 with an outer cylindrical jacket 2. The reaction chamber 1 is essentially ring-shaped because it has a cylindrical recess 3 on the inside, which is delimited by an inner wall 4 made of a material that is a good conductor of heat.

In den Reaktor 5, der in stehender Bauart ausgeführt ist, kann unten über die Zuleitung 6 ein vorgewärmtes Prozeßgas (z.B. Äthylbenzoldämpfe) eingeleitet werden. Dieses Prozeßgas strömt zunächst in einen ringförmigen Verteilraum 22 und von dort nach oben in den eigentlichen Reaktionsraum 1, der z.B. mit einem Katalysator gefüllt ist. Nach Durchströmen der Katalysatormasse ist das Prozeßgas in ein Produktgas (z.B. Styrol) umgewandelt und tritt am oberen Ende 12 des Reaktors 5 durch die Produktgasableitung 7 aus dem Reaktionsraum 1 aus. Um die endotherme Reaktion im Reaktionsraum 1 in Gang zu halten, muß dieser mittels eines heißen Rauchgases beheizt werden. Hierzu ist am unteren Ende 13 des Reaktors 5 eine Rauchgaszuleitung 10 vorgesehen, durch die heiße Rauchgase unmittelbar in die zylinderförmige Aussparung 3 geleitet werden. Mit Vorteil wird die Rauchgaszuleitung 10 als Brennkammer 16 mit feuerfesten Wänden 15 ausgeführt, so daß die Rauchgaserzeugung direkt in dem Reaktor 5 erfolgen kann.A preheated process gas (for example ethylbenzene vapors) can be introduced at the bottom via the feed line 6 into the reactor 5, which is designed in a standing design. This process gas first flows into an annular distribution space 22 and from there up into the actual reaction space 1, which is filled, for example, with a catalyst. After flowing through the catalyst mass, the process gas is converted into a product gas (eg styrene) and exits from the reaction chamber 1 at the upper end 12 of the reactor 5 through the product gas discharge line 7. In order to keep the endothermic reaction in reaction space 1 going, it must be heated by means of a hot flue gas. For this purpose, a flue gas feed line 10 is provided at the lower end 13 of the reactor 5, through which hot flue gases are fed directly into the cylindrical recess 3. The flue gas feed line 10 is advantageously designed as a combustion chamber 16 with refractory walls 15, so that the flue gas can be generated directly in the reactor 5.

Hierzu weist die Brennkammer 16 am unteren Ende einen Brenner 19 auf, dem über die Leitungen 20 und 21 Brennstoff und ein sauerstoffhaltiges Gas zugeführt werden können. Im Inneren der Aussparung 3 schließt sich an die Rauchgaszuleitung 10 unmittelbar eine als rohrförmiger Körper 8 aus gut wärmeleitendem Material ausgebildete Barriere an. Dieser gasdichte rohrförmige Körper 8, der sich bis nahe an das obere Ende der zylinderförmigen Aussparung 3 erstreckt, schirmt die innere Wand 4 des Reaktionsraums 1 zunächst vor einem direkten Kontakt mit dem heißen Rauchgas ab und bildet mit der Wand 4 einen Ringspalt 9. Dieser Ringspalt 9 ist oben zum Inneren der zylinderförmigen Aussparung 3 offen. Das von dem Brenner 19 erzeugte heiße Rauchgas strömt daher zunächst an dem rohrförmigen Körper 8 entlang nach oben, wird am oberen Ende des rohrförmigen Körpers 8 nach außen umgelenkt und strömt schließlich in umgekehrter Richtung an der Außenseite des rohrförmigen Körpers 8 durch den Ringspalt 9 nach unten, wo es durch die am unteren Ende 13 befindliche Rauchgasableitung 11 abgeleitet werden kann.For this purpose, the combustion chamber 16 has a burner 19 at the lower end, to which fuel and an oxygen-containing gas can be supplied via the lines 20 and 21. In the interior of the cutout 3, a flue gas supply line 10 is directly connected to a barrier designed as a tubular body 8 made of a material which is a good heat conductor. This gas-tight tubular body 8, which extends close to the upper end of the cylindrical recess 3, initially shields the inner wall 4 of the reaction chamber 1 from direct contact with the hot flue gas and forms an annular gap 9 with the wall 4. This annular gap 9 is open at the top to the interior of the cylindrical recess 3. The hot flue gas generated by the burner 19 therefore initially flows upwards along the tubular body 8, is deflected outwards at the upper end of the tubular body 8 and finally flows downwards in the opposite direction on the outside of the tubular body 8 through the annular gap 9 where it can be discharged through the flue gas discharge line 11 located at the lower end 13.

Das durch den Ringspalt 9 abwärts strömende Rauchgas gibt ständig Wärme über die Wand 4 an das im Gegenstrom durch den Reaktionsraum 1 strömende Prozeßgas ab und ermöglicht dort die endotherme Reaktion. Da gleichzeitig auf der Innenseite des rohrförmigen Körpers 8 heißes Rauchgas entlangströmt und Wärme an den rohrförmigen Körper 8 abgibt, wird ein Teil dieser Wärme auf den abwärtsströmenden Strömungsabschnitt des Rauchgasstromes übertragen, so daß dessen Temperatur trotz der fortlaufenden Wärmeabgabe an das Prozeßgas vergleichsweise langsam abnimmt.The flue gas flowing downward through the annular gap 9 continuously gives off heat via the wall 4 to the process gas flowing in countercurrent through the reaction space 1 and enables the endothermic reaction there. Since at the same time hot flue gas flows along the inside of the tubular body 8 and emits heat to the tubular body 8, part of this heat is transferred to the downward flowing section of the flue gas stream, so that its temperature decreases comparatively slowly despite the continuous heat emission to the process gas.

Das Ausmaß des Wärmeaustauschs zwischen den beiden Strömungsabschnitten des Rauchgasstromes sowie zwischen dem abwärtsströmenden Rauchgasstrom und dem Prozeßgasstrom läßt sich durch die Wahl des Durchmessers des rohrförmigen Körpers beeinflussen, da ein größerer Durchmesser bei sonst gleichen Bedingungen eine Verringerung des Ringspaltes 9 und somit eine Erhöhung der Strömungsgeschwindigkeit im abwärts gerichteten Strömungsabschnitt des Rauchgases bewirkt, so daß das Rauchgas infolge des intensivierten Wärmeaustauschs (Konvektion) mit der inneren Wand 4 des Reaktionsraums 1 bei einer geringeren Temperatur in die Rauchgasableitung 11 eintritt. Besonders wirksam läßt sich der Wärmeaustausch zwischen den beiden entgegengesetzt gerichteten Strömungsabschnitten des Rauchgases dadurch beeinflussen, daß im Inneren der zylinderförmigen Aussparung 3 im Bereich von deren Längsachse ein Strömungsverdrängungskörper 14 angeordnet wird, der sich etwa über die Länge des rohrförmigen Körpers 8 erstreckt und den aufwärts gerichteten Strömungsabschnitt des Rauchgasstromes in der Nähe der Innenoberfläche des rohrförmigen Körpers 8 hält. Die Strömungsgeschwindigkeit des aufwärts gerichteten Rauchgasstromes steigt entsprechend der Querschnittsverminderung an, so daß ein verbesserter Wärmeaustausch durch Konvektion zustandekommt.The extent of the heat exchange between the two flow sections of the flue gas flow and between the downward flowing flue gas flow and the process gas flow can be influenced by the choice of the diameter of the tubular body, since a larger diameter, with otherwise the same conditions, reduces the annular gap 9 and thus increases the flow velocity in the causes downward flow section of the flue gas, so that the flue gas due to the intensified heat exchange (convection) with the inner wall 4 of the reaction chamber 1 enters the flue gas discharge line 11 at a lower temperature. The heat exchange between the two oppositely directed flow sections of the flue gas can be influenced particularly effectively by arranging a flow displacement body 14 in the interior of the cylindrical recess 3 in the region of its longitudinal axis, which body extends approximately over the length of the tubular body 8 and the upward-facing one Flow section of the flue gas stream in the vicinity of the inner surface of the tubular body 8 holds. The flow rate of the upward flue gas stream increases in accordance with the reduction in cross section, so that an improved heat exchange by convection takes place.

Das aus der Brennkammer 16 entlang dem rohrförmigen Körper 8 nach oben strömende Rauchgas führt zu einer starken Erwärmung der Wand des rohrförmigen Körpers 8, wobei deren Temperatur mit zunehmender Höhe abnimmt. Daher ist die Wärmestrahlung der Wand des rohrförmigen Körpers 8 auf die Wand 4 des Reaktionsraums 1 im unteren Teil deutlich stärker als im oberen Teil. Dies führt zu einem weitgehenden Ausgleich der Temperatur in der Wand 4 über die Länge des Reaktionsraums 1, so daß sich auch im Inneren des Reaktionsraums 1 weitgehend isotherme Verhältnisse einstellen.The flue gas flowing upward from the combustion chamber 16 along the tubular body 8 leads to a strong heating of the wall of the tubular body 8, the temperature of which decreases with increasing height. Therefore, the heat radiation from the wall of the tubular body 8 to the wall 4 of the reaction chamber 1 is significantly stronger in the lower part than in the upper part. This leads to an extensive compensation of the temperature in the wall 4 over the length of the reaction space 1, so that largely isothermal conditions also occur in the interior of the reaction space 1.

Um die Umlenkung der Rauchgasströmung am oberen Ende des rohrförmigen Körpers 8 zu erleichtern, ist der Reaktionsraum 1 auf der Innenseite oben mit einem etwa kuppelförmigen Boden 18 ausgeführt. Wegen der ständigen Wärmeabgabe im Bereich des aufwärts gerichteten Rauchgasstromes kann dessen Temperatur bis zum Erreichen des oberen Endes des rohrförmigen Körpers 8 und damit bis zum Erreichen des kuppelförmigen Bodens 18 gezielt mindestens so weit abgesenkt werden, daß der direkte Kontakt des Rauchgases mit der mechanisch belasteten Innenwand 4 des Reaktionsraums 1 nicht mehr zu thermischen Schädigungen führt.In order to facilitate the deflection of the flue gas flow at the upper end of the tubular body 8, the reaction chamber 1 is designed with an approximately dome-shaped bottom 18 on the inside. Because of the constant heat emission in the area of the upward flue gas stream, its temperature can be reduced at least to such an extent that the direct contact of the flue gas with the mechanically stressed inner wall until the upper end of the tubular body 8 and thus until the dome-shaped bottom 18 is reached 4 of the reaction chamber 1 no longer leads to thermal damage.

Zur Verbesserung des thermischen Wirkungsgrades kann der Reaktor 5 außen mit einer Wärmeisolierung 17 versehen sein, die die Abstrahlungsverluste vermindert. Darüberhinaus empfiehlt es sich in manchen Fällen, in denen der Brenner ein Rauchgas mit sehr hoher Temperatur erzeugt, einen Teil des abgekühlten Rauchgases, das durch die Rauchgasableitung 11 abgeleitet wird, in den Brenner 19 bzw. in den Brennraum 16 zurückzuführen, um dort die Rauchgastemperatur zu vermindern. Wenngleich der Wärmeaustausch zwischen dem Rauchgas und dem Prozeßgas zweckmäßigerweise im Gegenstromverfahren durchgeführt wird, insbesondere, wenn die Vorwärmung des Prozeßgases nicht bis auf Reaktionstenperatur erfolgt, so ist es dennoch nicht ausgeschlossen, die Erfindung auch nach dem Gleichstromprinzip auszuführen. Vorteilhafterweise wird das Gehäuse im unteren Teil 13 des Reaktors 5 aus feuerfestem Material ausgeführt, ebenso der Strömungsverdrängungskörper 14, der als Vollstab oder auch als Rohr mit mindestens einem geschlossenen Ende ausgebildet sein kann. Für den Mantel 2, die Wände 4 und den rohrförmigen Körper 8 empfehlen sich metallische Werkstoffe.To improve the thermal efficiency, the outside of the reactor 5 can be provided with thermal insulation 17, which reduces the radiation losses. In addition, it is advisable in some cases, in which the burner generates a flue gas with a very high temperature, to return part of the cooled flue gas, which is discharged through the flue gas discharge line 11, to the burner 19 or the combustion chamber 16 in order to return the flue gas temperature there to diminish. Although the heat exchange between the flue gas and the process gas is expediently carried out in a countercurrent process, in particular if the preheating of the process gas does not take place to the reaction temperature, it is nevertheless not impossible to carry out the invention according to the direct current principle. Advantageously, the housing in the lower part 13 of the reactor 5 is made of refractory material, as is the flow displacement body 14, which can be designed as a solid rod or as a tube with at least one closed end. Metallic materials are recommended for the casing 2, the walls 4 and the tubular body 8.

In Figur 2 ist eine abgewandelte Ausführung der Erfindung dargestellt, wobei funktionsgleiche Teile mit den gleichen Bezugszeichen versehen wurden wie in Figur 1.FIG. 2 shows a modified embodiment of the invention, functionally identical parts being provided with the same reference numerals as in FIG. 1.

Der dort dargestellte Reaktor 5 weist mehrere zylinderförmige Aussparungen 3 auf, die parallel zueinander angeordnet und deren zylinderförmige Wände 8 jeweils gasdicht mit den Löchern eines Lochbodens 24 verbunden sind. Die in die Aussparungen 3 von unten koaxial eingeführten rohrförmigen Körper 8 sind jeweils gasdicht mit den Löchern eines zweiten Lochbodens 23 verbunden, der die Brennkammer 16 nach oben hin abschließt, so daß die heißen Rauchgase zwangsläufig durch die rohrfömigen Körper 8 nach oben steigen, an deren oberen Enden im Bereich der kuppelförmigen Böden 18 jeweils umgelenkt und durch die Ringspalte 9 nach unten geführt werden. Der Wärmeaustausch zwischen den Rauchgasströmungsabschnitten und dem Prozeßgas geschieht in gleicher Weise wie in Figur 1. Nach Durchströmen der Ringspalte 9 sammelt sich das abgekühlte Rauchgas in dem Raum zwischen den beiden Lochböden 23 und 24 und tritt dann durch die Rauchgasableitung 11 unten aus dem Gehäuse des Reaktors 5 heraus.The reactor 5 shown there has a plurality of cylindrical recesses 3, which are arranged parallel to one another and whose cylindrical walls 8 are each gas-tightly connected to the holes in a perforated base 24. The tubular bodies 8 coaxially inserted into the recesses 3 from below are each gas-tightly connected to the holes of a second perforated base 23, which closes off the combustion chamber 16 at the top, so that the hot flue gases inevitably rise upwards through the tubular bodies 8, on the latter upper ends in the region of the dome-shaped bottoms 18 are each deflected and guided downward through the annular gaps 9. The heat exchange between the flue gas flow sections and the process gas takes place in the same way as in Figure 1. After flowing through the annular gaps 9, the cooled flue gas collects in the space between the two perforated plates 23 and 24 and then exits through the flue gas discharge line 11 from the bottom of the housing of the reactor 5 out.

Die Erfindung bringt insbesondere folgende Vorteile mit sich: Der Reaktor ist äußerst einfach aufgebaut und verursacht daher vergleichsweise geringe Herstellkosten. Der Wärmestrom durch die Wand des Reaktionsraums hindurch ist gleichmäßig und kann einem optimalen Höchstwert angenähert werden, der die thermische Belastbarkeit der verwendeten Werkstoffe vollständig berücksichtigt. Probleme infolge einer direkten Beaufschlagung mechanisch belasteter Teile durch eine offene Flamme oder zu heiße Rauchgase werden vermieden. Da die endotherme Reaktion praktisch unter isothermen Bedingungen stattfinden kann, ist eine hohe Effizienz des Reaktionsraumvolumens gesichert. Dank der dadurch möglichen vergleichsweise kleinen Bauweise bei vorgegebener Leistung lassen sich die Abstrahlungsverluste minimieren. Zur äußeren Wärmeisolierung sind keine feuerfesten Materialien erforderlich; diese empfehlen sich lediglich im Bereich der Rauchgaszu- und ableitung.The invention has the following advantages in particular: The reactor is extremely simple in construction and therefore causes comparatively low production costs. The heat flow through the wall of the reaction chamber is uniform and can be approximated to an optimal maximum value that takes full account of the thermal load-bearing capacity of the materials used. Problems due to direct exposure to mechanically stressed parts from an open flame or too hot flue gases are avoided. Since the endothermic reaction can practically take place under isothermal conditions, a high efficiency of the reaction space volume is ensured. Thanks to the comparatively small design that is possible with a given output, the radiation losses can be minimized. No fireproof materials are required for external heat insulation; these are only recommended in the area of flue gas supply and discharge.

Claims (11)

1. Verfahren zur indirekten Beheizung eines Prozeßgasstroms in einem Reaktionsraum für eine endotherme, insbesondere katalytische Reaktion, bei dem die Wände des Reaktionsraums an der außerhalb des Reaktionsraums gelegenen Oberfläche von einem heißen Rauchgas umströmt werden und die von den Wänden aufgenommene Wärme an das Prozeßgas abgegeben wird, wobei das heiße Rauchgas zunächst an einer aus einem wärmeleitenden und wärmebeständigen Material gebildeten Barriere unter Abgabe von Wärme an diese Barriere entlanggeführt wird, wobei ferner das Rauchgas nach Erreichen einer für die Wände des Reaktionsraums unschädlichen Temperatur umgelenkt und auf der gegenüberliegenden Seite der Barriere in entgegengesetzter Richtung weitergeführt und erst dabei in Kontakt mit der Außenseite der Wände des Reaktionsraums gebracht wird und wobei das in entgegengesetzter Richtung weitergeführte Rauchgas einerseits von der Barriere Wärme aufnimmt und andererseits Wärme an die Wände des Reaktionsraums abgibt,
dadurch gekennzeichnet,
daß das heiße Rauchgas vor seiner Umlenkung über die gesamte axiale Länge des Reaktionsraums an der Barriere entlanggeführt wird und die Strömungsgeschwindigkeiten des Rauchgasstromes in den Strömungsabschnitten vor und nach der Umlenkung unter Berücksichtigung sowohl des Wärmetauschs zwischen dem Rauchgas und dem Reaktionsraum als auch des durch die Barriere hindurch erfolgenden Wärmetauschs zwischen den entgegengesetzten Strömungsabschnitten des Rauchgases als auch des Wärmetauschs durch Wärmestrahlung zwischen der Barriere und den Wänden des Reaktionsraums so zueinander eingestellt werden, daß die Wärme aufnehmenden Wände des Reaktionsraums über die axiale Länge weitgehend gleiche Temperatur aufweisen.
1. A method for indirect heating of a process gas stream in a reaction space for an endothermic, in particular catalytic reaction, in which a hot flue gas flows around the walls of the reaction space on the surface outside the reaction space and the heat absorbed by the walls is given off to the process gas , wherein the hot flue gas is first passed along a barrier formed from a heat-conducting and heat-resistant material with the emission of heat to this barrier, the flue gas also being deflected after reaching a temperature which is harmless to the walls of the reaction space and on the opposite side of the barrier in the opposite direction Direction is continued and only then brought into contact with the outside of the walls of the reaction space and the flue gas carried in the opposite direction on the one hand absorbs heat from the barrier and on the other hand heat to the walls of the reaction space,
characterized,
that the hot flue gas is guided along the barrier over the entire axial length of the reaction space before it is deflected, and the flow velocities of the flue gas flow in the flow sections before and after the deflection taking into account both the heat exchange between the flue gas and the reaction space and that through the barrier heat exchange taking place between the opposite flow sections of the flue gas and the heat exchange by heat radiation between the barrier and the walls of the reaction space are adjusted so that the heat-absorbing walls of the reaction space have largely the same temperature over the axial length.
2. Verfahren nach Anspruch 1,
dadurch gekennzeichnet,
daß der Prozeßgasstrom im Gegenstrom zu dem an den Wänden des Reaktionsraums entlanggeführten Rauchgasstrom geführt wird.
2. The method according to claim 1,
characterized,
that the process gas stream is conducted in countercurrent to the flue gas stream which is guided along the walls of the reaction space.
3. Reaktor für die Durchführung des Verfahrens nach Anspruch 1, mit einem Reaktionsraum (1), der außen von einem zylindrischen Mantel (2) eingeschlossen und in dem mindestens eine sich im wesentlichen über die Länge des Reaktionsraums (1) sich erstreckende und parallel zu dessen Längsachse gerichtete zylindrische Aussparung (3) gebildet ist, die jeweils durch eine innere Wand (4) aus einem gut wärmeleitenden Material von dem Reaktionsraum (1) abgetrennt ist, mit einer an einem Ende (13) des Reaktors (5) angeordneten Prozeßgaszuleitung (6) zum Reaktionsraum (1) und einer an einem Ende (12) des Reaktors (5) angeordneten Produktgasableitung (7) aus dessen Reaktionsraum (1), mit jeweils einem zu der oder den Aussparungen (3) koaxialen rohrförmigen Körper (8), der einen Ringspalt (9) mit der inneren Wand (4) des Reaktionsraums (1) bildet, und mit einer Rauchgaszuleitung (10) und einer Rauchgas­ableitung (11), die mit dem Ringspalt (9) in Verbindung stehen,
dadurch gekennzeichnet,
daß der rohrförmige Körper (8) sich jeweils innerhalb der zylindrischen Aussparung (3) über nahezu die gesamte Länge des Reaktionsraums (1) erstreckt,
daß die Prozeßgaszuleitung (6) und die Produktgasableitung (7) an gegenüberliegenden Enden (13, 12) des Reaktors (5) angeordnet sind, daß die Rauchgaszuleitung (10) und die Rauchgasableitung (11) am gleichen Ende (13) des Reaktors (5) angeordnet sind,
daß die Rauchgaszuleitung (10) unmittelbar in das Innere des rohrförmigen Körpers (8) geführt ist und
daß der Ringspalt (9) an dem der Rauchgaszuleitung (10) gegenüberliegenden Ende (12) zum Inneren des rohrförmigen Körpers (8) offen ist.
3. Reactor for carrying out the method according to claim 1, with a reaction space (1) which is enclosed on the outside by a cylindrical jacket (2) and in which at least one extends substantially parallel to the length of the reaction space (1) the longitudinal axis of which is formed with a cylindrical recess (3), each of which is separated from the reaction chamber (1) by an inner wall (4) made of a good heat-conducting material, with a process gas supply line () arranged at one end (13) of the reactor (5) 6) to the reaction space (1) and a product gas discharge line (7) from its reaction space (1) arranged at one end (12) of the reactor (5), each having a tubular body (8) coaxial with the recesses (3), which forms an annular gap (9) with the inner wall (4) of the reaction space (1), and with a flue gas feed line (10) and a flue gas discharge line (11) which are connected to the annular gap (9),
characterized,
that the tubular body (8) extends within the cylindrical recess (3) over almost the entire length of the reaction space (1),
that the process gas supply line (6) and the product gas discharge line (7) are arranged at opposite ends (13, 12) of the reactor (5), that the flue gas supply line (10) and the flue gas discharge line (11) are located at the same end (13) of the reactor (5 ) are arranged,
that the flue gas supply line (10) is led directly into the interior of the tubular body (8) and
that the annular gap (9) is open at the end (12) opposite the flue gas supply line (10) to the interior of the tubular body (8).
4. Reaktor nach Anspruch 3,
dadurch gekennzeichnet,
daß die Produktgaszuleitung (6) an dem Ende (13) des Reaktors (5) angeordnet ist, an dem sich die Rauchgaszu- und -ableitung (10,11) befinden.
4. Reactor according to claim 3,
characterized,
that the product gas supply line (6) is arranged at the end (13) of the reactor (5) at which the flue gas supply and discharge lines (10, 11) are located.
5. Reaktor nach Anspruch 3 oder 4,
dadurch gekennzeichnet,
daß im Inneren des rohrförmigen Körpers (8) ein koaxialer Strömungsverdrängungskörper (14) für das heiße Rauchgas angeordnet ist.
5. Reactor according to claim 3 or 4,
characterized,
that a coaxial flow displacement body (14) for the hot flue gas is arranged inside the tubular body (8).
6. Reaktor nach einem der Ansprüche 3 bis 5,
dadurch gekennzeichnet,
daß die Zuleitung (10) für das heiße Rauchgas als Brennkammer (16) mit feuerfesten Wänden (15) ausgebildet ist.
6. Reactor according to one of claims 3 to 5,
characterized,
that the feed line (10) for the hot flue gas is designed as a combustion chamber (16) with refractory walls (15).
7. Reaktor nach Anspruch 6,
dadurch gekennzeichnet,
daß die Ableitung (11) des abgekühlten Rauchgases eine Leitungsverbindung zur Brennkammer (16), über die ein Teilstrom des Rauchgases in die Brennkammer (16) rückführbar ist, aufweist.
7. Reactor according to claim 6,
characterized,
that the discharge line (11) of the cooled flue gas has a line connection to the combustion chamber (16) via which a partial flow of the flue gas can be returned to the combustion chamber (16).
8. Reaktor nach einem der Ansprüche 3 bis 7,
dadurch gekennzeichnet,
daß der Reaktionsraum (1) außen mit einer Wärmeisolierung (17) versehen ist.
8. Reactor according to one of claims 3 to 7,
characterized,
that the reaction chamber (1) is provided on the outside with thermal insulation (17).
9. Reaktor nach einem der Ansprüche 3 bis 8,
dadurch gekennzeichnet,
daß der Reaktor (5) in stehender Bauart ausgeführt ist.
9. Reactor according to one of claims 3 to 8,
characterized,
that the reactor (5) is designed in a standing design.
10. Reaktor nach Anspruch 9,
dadurch gekennzeichnet,
daß das Reaktorende (13) mit der Rauchgaszu- (10) und -ableitung (11) unten angeordnet ist.
10. Reactor according to claim 9,
characterized,
that the reactor end (13) with the flue gas supply (10) and discharge (11) is arranged below.
11. Reaktor nach einem der Ansprüche 3 bis 10,
dadurch gekennzeichnet,
daß der Reaktionsraum (1) im Bereich der offenen Verbindungsstelle zwischen dem Ringspalt (9) und dem Inneren des rohrförmigen Körpers (3) eine kuppelförmige Wand (18) aufweist.
11. Reactor according to one of claims 3 to 10,
characterized,
that the reaction space (1) has a dome-shaped wall (18) in the region of the open connection point between the annular gap (9) and the interior of the tubular body (3).
EP90250017A 1989-01-24 1990-01-22 Process and apparatus for indirectly heating a process gas stream in a reaction space for an endothermal reaction Expired - Lifetime EP0380192B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT8947570A IT1232200B (en) 1989-01-24 1989-01-24 ISOTHERMAL CATALYTIC REACTOR FOR ENDOTHERMAL REACTIONS
IT4757089 1989-01-24

Publications (2)

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EP0380192A1 true EP0380192A1 (en) 1990-08-01
EP0380192B1 EP0380192B1 (en) 1992-04-22

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EP (1) EP0380192B1 (en)
JP (1) JPH0714473B2 (en)
DE (1) DE59000093D1 (en)
DK (1) DK0380192T3 (en)
IT (1) IT1232200B (en)

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Also Published As

Publication number Publication date
DK0380192T3 (en) 1992-06-29
JPH0714473B2 (en) 1995-02-22
IT1232200B (en) 1992-01-28
EP0380192B1 (en) 1992-04-22
JPH03127A (en) 1991-01-07
IT8947570A0 (en) 1989-01-24
DE59000093D1 (en) 1992-05-27
US5162104A (en) 1992-11-10

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